1. Field of the Invention
The invention relates to a power transmission apparatus.
2. Related Art
JP-A-2005-233374 discloses a power transmission apparatus.
The power transmission apparatus is used as a transfer apparatus mounted in a front wheel-side of a four-wheel driving vehicle. A first rotary member and a second rotary member are rotatably supported in a transfer case, which serves as a case of the power transmission apparatus, by bearings. The first rotary member and the second rotary member interlock with each other by an engagement of a pair of bevel gears (ring gear and pinion gear).
The transfer case is divided into a case body and a case cover which are mainly arranged in a width direction of the transfer case. The case body and the case cover are joined with each other on mating surfaces thereof and are fastened by a plurality of bolts.
In the transfer apparatus, the mating surfaces are positioned at an outer periphery side of one of bearings supporting the first rotary member.
The mating surfaces of the transfer case should be formed with bolt holes, into which the bolts are screw-engaged, in a thickness part of the transfer case in the width direction and the transfer case protrudes outwards in the width direction, so that the transfer case is enlarged in the width direction. In contrast, if the mating surfaces are moved inwards in the width direction so as to suppress the enlargement of the transfer case in the width direction, it is not possible to form the bolt holes, into which the bolts are screw-engaged, in the thickness part of the transfer case and the bolt holes penetrate into an inside of the transfer case. As a result, it is difficult to make the transfer case smaller.